submachine
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Producing Oleum at Room Temperature!
Ran across this process and thought I would share it here. I have a LOT of sulphur and thought this process looked promising for a DIY version of
Sulphuric Acid.
Take a look, would love to hear from anyone that has heard of this or tried it. Looks like it could be promising.
The University of Waterloo, Ontario, has developed a novel process that uses an activated carbon catalyst to oxidize moist SO2. A solvent is then used
to recover H2SO4 and industrial solvents from the oxidation product. Certain carbons exhibit hourly production rates for SO3 at 25 °C that approach 3
g of SO3 (as H2SO4)/g catalyst. This rate appears to be several hundred times greater than the production rate over conventional vanadia catalysts
operating between 300 and 400 °C. Moreover, at 25 °C, the oxidation goes to completion. In contrast, in the conventional process, single-pass
conversions are limited to ~95%, so that tail gas processing is necessary.
A catalytic process for oxidizing SO2. original article
Canadian Patent
[Edited on 26-9-2012 by submachine]
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watson.fawkes
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No oleum from this process
Oleum? Please read the article you posted more carefully. First, SO3 comes off in the organic solvent used to scrub it from the catalyst
bed. It does not come off as a gas. Second, the maximum sulfuric acid concentration possible is stated as 1-2 N.
It's also a fairly slow process. The maximum production rate, as seen on the graph, is about 2.8 g acid per g catalyst, and that's at a (calibrated)
6% SO2 input gas. It seems that it would be just fine for a small lab plant, if you need the relatively dilute acid product. This property
alone means it's unlikely to displace the contact process anytime soon, which has much higher SO2 processing rate.
Catalyst preparation isn't simple, requiring non-OTC materials, vacuum degassing, and extrusion forming. (See page 12 of the typescript patent
application.) Two separate catalyst steps are required, each adding their own adjunct to the carbon substrate. In addition, it's not even clear that
the catalyst recipe is complete. There isn't an explicit single preferred embodiment of the catalyst, just laundry list of things that might go in at
each step.
I have to say that the patent disclosure fairly badly written. It suffers overall from inadequate disclosure. In several different ways it looks like
someone of ordinary skill in the art doesn't have enough information to reproduce the process in its entirety. This kind of defect can render patents
invalid; this one might fall if it ever became an issue. It looks like they filed the patent based on a few bench-scale experiments; it shows.
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